1. Field of the Invention
The present invention relates to a self-luminescent plasma display panel (hereinafter referred to as PDP) that utilizes gas discharge. Precisely, it relates to PDP having a specifically designed phosphor screen, and to a method for forming the phosphor screen.
2. Description of the Related Art
Generally, PDP comprises two opposing glass substrates each having an electrode formed thereon, and a phosphor layer. This is so constructed that the two opposing glass substrates are held to have a predetermined cell space therebetween, and a vapor consisting essentially of Ne, Xe and the like is sealed in the cell space. Voltage is applied between the electrodes for attaining electric discharge in fine cell spaces around them, whereby the phosphor layer provided in each cell space is excited to emit light for displaying various informations. U.S. Pat. Nos. 5,674,553 and 5,661,500 disclose the related art for PDP.
PDP is composed of display regions that participate in displaying various informations and non-display regions that interspace the display regions while not participating in information displaying. In PDP of the related art, phosphor layers that participate in displaying are provided between linear ribs adjacent to each other, and they are in both the display regions and the non-display regions while extending along the linear ribs in their lengthwise direction.
The first problem with PDP of the related art is that the UV rays as generated through discharge in the display regions leak to the non-display regions not having ribs therearound, thereby exciting the phosphor layers in the non-display regions to emit light.
Concretely, the problem is that the phosphor in the non-image regions emits light to brighten the non-image regions. In addition, the light as emitted by the phosphor in the non-image regions leaks to the adjacent image regions to thereby brighten the image regions to a higher degree over their original brightness.
The second problem with the related art PDP is that the UV rays as generated through discharge in the display regions excite the phosphor layers therein to emit light, and the thus-emitted light leaks to the non-image regions.
In this connection, the color of the phosphor layers not emitting light is white or pale gray similar to white. Therefore, the third problem with the structure of the related art PDP is that the color of the phosphor layers is seen through the front plate of PDP owing to the ambient light entering them.
Concretely, when PDP is used in light, the ambient light entering it is scattered on the phosphor layers in the non-image regions. Therefore, the problem is that the non-image regions are seen nearly whitish.
In addition, when PDP is used in light, the ambient light entering it partly passes through the phosphor layers and is scattered on the dielectric layers underlying the phosphor layers. The scattered light again enters the phosphor layers and is further scattered on the phosphor layers in the non-image regions. This brings about the fourth problem that the non-image regions are seen nearly whitish.
All these problems cause the decrease in the contrast and the sharpness of the image informations and others displayed in PDP.